Door latch



Feb. 19, 1957 E. M. BORCHERS ETAL 2,782,061

DOOR LATCH Filed Jan. 7, 1954 2 Sheets-Sheet l 48 a; a r-1! INVENTOR5 M. BORCHE AxEL WI AHLGREN 1957 E. M. BORCHERS ETAL 2,782,061

DOOR LATCH Filed Jan. 7, 1954 v 2 Sheets-Sheet 2 F I 26 53 o 5' AL W 2 i, /1 v I8 f 2 ll H 2o 54 T? 28. 5 Q1" "g 15 so 5| 5 l4- 1e Fig.6 22 48 50 ll: Z6 za INVENTORS EARL M. BORCHERS BY AXEL HAHLGREN llnited States Patent noon LATCH Earl M. Rorchers and Axel W. Ahlgren, Rockford, Ill., assignors to Amerock Corporation, a corporation of Illinois 7 Application January 7, 1954, Serial N 0. 402,622

8 Claims. (Cl. 292-169) The present invention relates in general to snap-action door latches such as are commonly employed on screen doors. Such latches usually incorporate means operable from the inside of the door for locking the bolt against withdrawal by operation of the outside handle.

Prior snap-acting door latches have employed, in general, either of two types of arrangements for locking the bolt so that the door, when closed, cannot be opened. In the first arrangement, the bolt itself is locked against translation relative to the latch casing, so that the bolt no longer has snap-action. This has the marked disadvantage that if the bolt is locked while the door is open, the bolt bangs against the strike plate on the jamb as the door swings shut, thus presenting the possibility of damaging either the bolt itself or the strike plate and jamb and leaving the door ajar. In the second arrangement, the bolt is locked by locking some part of the mechanism for re tracting it upon actuation of the latch handles. This is characterized by the disadvantage that if the locking means are set while the door is open, the bolt may snap into latched engagement with the jamb as the door swings shut, leaving the locking means set and the bolt locked against retraction. A person opening the door from the inside, and inadvertently setting the locking means on his way out, may thus be locked outside when the door swings closed.

The general aim of the invention is to provide a novel snap'acting door latch which overcomes these difliculties.

It is an object of the invention to provide such a door latch having improved and simplified means for locking the same.

More specifically, it is an object of the invention to provide such a door latch having locking means operable from one side, e. g., the inside, of the door which, when set, leaves the bolt free for snap-action so that the bolt cannot bang against the jamb, together with means for disabling the locking means upon shifting of the bolt so that the latter cannot remain locked, when set while the door is open, after the door has swung closed.

Another object is the provision of improved and simplified means for locking a door latch so that the bolt cannot be retracted by operation of the handles.

And a further object is to provide such a door latch which is compact, rugged and inexpensive in construction, yet reliable in operation. I

Other objects and advantages will become apparent as the following description proceeds, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a plan view of a door latch embodying the features of the present invention and shown in connection with a typical door which appears in section;

Fig. 2 is an elevation of the door latch and a part of the door, taken from the inside of the door;

Fig. 3 is a side elevation, partially in section, taken substantially along the line 33 in Fig. 2;

Fig. 4 is a sectional view taken substantially along the line 44 in Fig. 2; a l

Fig. 5 is a vertical section taken substantially along the oflset planes represented by the line 5--5 in Fig. 4; and

Fig. 6 is a vertical section taken substantially along the oifset planes represented by the line 6-6 in Fig. 5.

While the invention is shown and described in some detail with reference to a particular embodiment thereof, there is no intention that it thus be limited to such detail. On the contrary, it is intended here to cover all alterations, modifications, and equivalents falling within the spirit and scope of the invention as defined by the appended claims.

Referring now to the drawings, the exemplary door latch embodying the invention is here illustrated as applied to a door 10 mounted on a hinge 11 for swinging movement, the swinging edge of the door, when closed, abutting against a shoulder 12 on the jamb 14. The jamb is provided with a latching cavity 15 for receiving a snap-acting bolt, and a protective strike plate 16 having an opening registering with the entrance to the cavity 15.

In order to make clear one environment of the invention, the background details of the construction of the present latch will be briefly considered. As shown best in Figs. 1 and 2, the latch comprises a case 18 adapted, as by flat-headed screws 19, to be mounted on the inside surface of the door 10. A latch bolt 20 is slid-ably mounted in the case to be moved between latched engagement with the cavity 15 and a retracted position free of the door jamb 14. Means are provided for biasing the latch bolt 20 into the cavity 15, and the bolt is retractable upon rotation of inside or outside handles 22 or 23.

In greater detail, the latch bolt 20 is formed with a fiat portion Zita slidable over a base plate 26 and with a nosepiece bent back upon itself to provide an inclined surface 25 which cams against the strike plate 16 to shift thebolt to the left (Fig. 4) as the door swings closed. For retracting the bolt 26, the usual double-armed cam actuator 27 is rotatably disposed in the case 18 and connected with the handles 21 and 22 by squared shanks socketed into its opposite sides. The actuator 27 is normally centered by a torsion spring 28. At its bifurcated rear end, the bolt 20 has the usual cam lugs 20]) and 200 located for engagement with the respective arms of the actuator 27. Rotation of the handles 22, 23 and the actuator 27 in either direction thus brings one of the actuator arms into camming engagement with its corresponding cam lug 20b or 200 to shift the latch bolt inwardly. During such translation of the bolt 20, it is guided in a channel-shaped bracket 30 which is keyed for support into the plate 26.

In accordance with the present invention, means are provided for locking the inside handle 22 and thereby the outer one 23, since both are connected to the actuator 27, against rotation. Additionally, there is provided means for disabling such locking means automatically when the bolt 20 is cammed to its retracted position as an incident to closure of the door.

The locking means as here embodied comprise a locking dog 45 carried by the inside handle 22 in a manner to be removably inserted into an opening or slot 46 defined in the case 18 immediately below the handle when the latter is in its centered or normal position. As here shown, the handle 22 has a passageway 48 which receives a locking lever 49 pivoted on a press-fitted pin 50. The lever includes a notched thumb portion 51 permitting it to be rocked about the pin 56, the locking dog 45 integral with the lever being thus inserted into or retracted from the slot 46. The lever 49 and slot 46 are disposed in radial relation to the axis of rotation of the handle, so that when the dog 45 is inserted into the slot, rotation of the handle relative to the case 18 cannot occur. With the door 10 closed and the latch bolt 20 engaged in the cavity 15, the latch is locked since the bolt cannot be withdrawn by turning either of the handles. Although the handle 22 is in this instance shown'a's being in the to avoid lock-out in case the door is permitted to close,

there is provided a disabling device arranged for actuation in response to the inward movement of the bolt 20 as it cams against the strike plate 16. The disabling device is operative upon thedog 45 to move it out of locking position relative to the casing 18. Inthe present in stance, this disabling deviceis in the form of a U-shaped lever 53, having spaced side portions 53a and 53b connected by a cross portion 530, and which is pivotally carried on a pin 54 inserted through spaced, apertured lugs turned upwardly from the bracket 30. For connecting the lever 53 to be rocked about its pivot pin 54 whenever the bolt 20 is moved, the flat portion 20a of the bolt includes keyways 20d (Fig. 4) formed on either side thereof which receive mating key tabs 53d on the respective side portions 53a and 53b. The interconnection between the lever 53 and the latching bolt 26 is thus in the nature of a rack and pinion, the lever being rocked counterclockwise about its pivot at 54 when the bolt 20 is retracted or shifted to the left, as viewed in Fig. 4. On the upper cross portion 53c, an integral projection or tab 55 is formed in such position that upon counterclockwise swing of the lever, the projection strikes the dog 45 to cam the same and push it clear of the slot 46. Thus, in the event that the door is opened and the locking dog 45 then inadvertently inserted into the slot 46, when the door closes and the latch bolt 20 is cammed to the left by engagement with the strike plate 16, the lever 53 is rocked counterclockwise to cause the projection 55 to disable the locking means by shifting the locking dog 45 clear of the casing 13.

In the present door latch, the biasing means for normally holding the latch bolt 20 in its extended position may conveniently be embodied in a coiled torsion spring 60 which is coaxially disposed on the pin 54. One end of the spring is inserted through an apertured car 61 upturned from the bracket 30, the other end of the spring bearing against the cross portion 530 of the lever 53. As a result the spring 60 rotationally biases the lever 53 in a clockwise direction (Fig. 4) and the lever by virtue of its gear-like connection formed by the key tabs 53d and the key slots 20a tends to shift the bolt 20 to its extended position. It will be seen that the spring 60 thus biases the latching bolt 20 to its extended position but permits the same to be withdrawn whenever the handles and the actuator 27 are rotated. By this arrangement, therefore, the pin 54 serves both as a pivot for the disabling lever 53 and at the same time mounts a biasing spring operative through the lever 53 on the bolt 20.

Referring to Figs. 1, 4, and 5, it will be seen that, when the lever 53 is in its outer position, the side portions 53a and 53b thereof which are inclined similarly to the front face of the bolt project outwardly from the casing 18 with the bolt for engagement with the door jamb 14 during closing movement of the door 10. As an incident to such engagement, the lever is shifted to its inner position in which the projection 55 enters the slot 46 to cam the dog 45 out of the slot and release the handles. Thus, the lever 53, in addition to being swung inwardly during rearward movement of the bolt by virtue of its connection through the keys 53d and the slots 20d, also is shifted inwardly by abutment of its projecting side members with the door jamb.

From the foregoing, the organization and operation of the present door latch are believed to be clear. However, by Way of brief summary, it may be pointed out that the door latch in the first instance provides a simple, compact, and sturdy latch mechanism which serves to latch and unlatch the door in the usual manner. That is, with the locking lever 49 thumbed to the position illustrated,.the door may be openedleither. from the out side or from the inside by rotating one of the handles 22 or 23 in either direction. This results in one of the actuator arms riding against the corresponding cam lug 20b or 200, to retract the bolt 20, against the force of its spring 60, clear of the cavity 15. Once the door has been unlatched in this manner and opened, the handles may be released and the torsion spring 28 returns them to their centered position. This permits the biasing spring 60, acting through the lever 53, to return the bolt 20 to its extended position. The door may be then swung closed and will be latched automatically due to the inclined surface 25 of the bolt striking the plate 16 and being shifted inwardly. With the door thus closed, the biasing spring-60 rocks the lever 53 clockwise and thus shifts the bolt 20 into latching engagement with the cavity 15.

With the door closed, the locking lever 49 may be thumbed counterclockwise (as viewed in Fig. 4) to insert the dog 45 into the slot 46. This effectively locks both the handles 22, 23 and the actuator 27 against rotation relative to the case 18 so that the bolt 20 cannot be withdrawn from the cavity 15. The latch bolt is thus effectively locked. To unlock the latch it is only necessary to rock the lever 49 clockwise to withdraw the dog 45 from the slot 46.

Additionally, itis impossible for the door to be first opened, and the locking lever 49 then swung down so that the dog 45 enters the slot 46, such that the bolt 20 is locked in its extended position and thus bangs against the strike plate 16when the door swings closed. Similarly, it is impossible for the locking dog 45 to be inserted into the slot 46 when the door is open such that the door may swing shut and latch in locked condition. If the door is first opened, and the locking lever 49 then rocked to insert the dog 45 into the slot 46, as the door swings shut and the bolt 20 is shifted into the case 18 by engagement of its inclined surface 25 with the strike plate 16, the lever 53 is rocked counterclockwise about its pivot at 54 through the connection 53d and 20d and by virtue of engagement of the projecting side portions 53a and 53b with the strike plate 16. The projection 55 thus strikes the dog 45 to swing it free of the slot 46. Therefore, as soon as the door swings shut, the bolt 20 is automatically latched but the locking means are disabled. This precludes a person being accidentally locked out if he inadvertently thumbs the locking lever 49 as he opens the door on his way out.

We claim as our invention:

1. In a door latch, the combination comprising a case, a bolt springbiased to extend from the case, means for retracting said bolt including a rotary handle, an opening in said case, a locking element including a dog carried by said handle and removably insertable into said opening to prevent rotation of the handle, and a projection movable with said bolt and into abutment with said element to. push said dog from said opening when the bolt member strikes an obstruction and is shifted thereby toward its retracted position, said projection thereby unlocking. said handle.

2. A door latch comprising, in combination, a case, a bolt .in said case, said bolt being translatable between extended andretracted positions, spring means biasing said bolt to its extended position, means including a handle for retracting saidbolt upon rotation of said handle, a slot defined in said case beneath a portion of said handle, a locking dog pivotedon said handle to swing into and out of said slot, and a lever pivoted in said case and connected to. said bolt to rock upon translation of said bolt, said lever having a projection positioned to strike said dog and swing it out of said slot when said bolt strikes an obstructionand is retracted by the same whereby said handle is freed for rotation.

3. In a door latch, the'combination comprising a case adapted..for;mounting,;on,,the swinging edge of a door, a bolt carried by said case in translatable .relation thereto for movement between extended and retracted positions, means biasing said bolt to its extended position, a handle mounted on said case to turn about an axis perpendicular to the plane of the door, means coupling said handle upon rotation thereof to retract said bolt, there being a slot defined in said case beneath said handle extending radially with respect to the axis of rotation of the handle, and a locking lever pivoted on said handle and having a dog swingable into or out of said slot to thereby lock or unlock said handle.

4. In a door latch, the combination of, a casing, a bolt reciprocable in said casing between advanced and retracted positions, means for retracting said bolt including a handle journaled on said casing, means on an exterior wall of said casing defining an opening, a locking element including a dog carried by said handle on the exterior of said wall and selectively shiftable into said opening to block rotation of the handle relative to said casing when the handle is in a position corresponding to said advanced position of said bolt, and a cam element mounted on the interior of said casing and movable into said opening from the inner side of said wall to abut said dog and shift the same out of said slot to release said handle as an incident to retraction of said bolt independently of said means for retracting the bolt.

5. In a door latch, the combination of, a casing member, a bolt reciprocable in said casing member between an advanced position and a retracted position and yieldably urged toward the latter, means including a handle member journaled on said casing member for retracting said bolt upon rotation of the handle member, means on one of said members defining an opening, a locking element including a dog carried by the other of said members and selectively shiftable into said opening to block relative rotation of said members when said handle member is in a position corresponding to the advanced position of said bolt, and a cam element movable with said bolt into camming engagement with said locking element to shift said dog out of said opening as an incident to retraction of the bolt independently of said means for retracting the bolt.

6. In a door latch, the combination of, a casing adapted to be mounted on the free side edge of a swinging door, a bolt reciprocable in said casing between advanced and retracted positions, means for retracting said bolt including a handle mounted on said casing to turn about an axis perpendicular to the plane of the door and having a part swingable back and forth along an exterior wall of the casing, means on said exterior wall defining an opening disposed opposite said handle part when the latter is in a position corresponding to said projected bolt position, and a locking element including a dog mounted on said handle part and selectively shiftable into said opening to lock said handle against rotation relative to said casing.

7. In a door latch, the combination of, a casing mem ber, a bolt reciprocable in said casing member between advanced and retracted positions and yieldably urged to- Ward the advanced position, a handle member mounted on said casing member for movement into and out of an unlatching position and connected to said bolt for retracting the latter during movement of the handle member out of the unlatching position, means on one of said members defining an opening, a locking element including a dog mounted on the other of said members for movement into and out of said opening when said handle member is in said unlatching position, said dog, when in said opening, abutting a defining edge thereof to block movement of said handle member out of said unlatching position, a cam element mounted on said casing member for movement back and forth between an outer position in which a part of the element projects beyond the casing member for engagement with the jamb of a door supporting the casing member during closing of the door and an inner position in which the cam element abuts said locking element to shift said dog out of said opening, and means acting between said casing member and said cam element and yieldably urging the latter toward said outer position, said cam element being shifted to said inner position upon engagement of said part thereof with the door jamb as an incident to closing the door.

8. In a door latch, the combination, of a casing mem ber, a bolt reciprocable in said casing member between advanced and retracted positions and yieldably urged toward the advanced position, a handle member mounted on said casing member for movement into and out of an unlatching position and connected to said bolt for retracting the latter during movement of the handle member out of the unlatching position, means on one of said members defining an opening, a locking element including a dog mounted on the other of said members for movement into and out of said opening when said handle member is in said unlatching position, said dog, when in said opening, abutting a defining edge thereof to block movement of said handle member out of said unlatching position, and a cam element movable with said bolt into camming engagement with said locking element to shift said dog out of said opening and release said handle member as an incident to retraction of the bolt independently of the handle member.

References Cited in the file of this patent UNITED STATES PATENTS 1,765,186 Vaicekauckas June 17, 1930 2,038,907 Schlage Apr. 28, 1936 2,246,828 Wolf et al June 24, 1941 2,479,256 Radcliffe Aug. 16, 1949 2,614,876 McConnell Oct. 21, 1952 

